1. Field of the Invention
The present invention relates to an LED (Light Emitting Diode) lamp device to be used as an indicating lamp, an illuminating lamp for a switch or the like, which is connected to a DC power source or an AC power source.
2. Description of Related Art
In case an LED lamp device is lighted by a commercial power source (normally 100 V-200 V), it has conventionally been normal practice to step down the voltage of the commercial power source to a low-voltage range (normally 24 V) that is suitable for an LED emitter (or illuminant) by means of a transformer or the like and then to convert it to DC and control the current value by means of a resistor or the like.
It has also been normal practice to convert the voltage of the commercial power source to a DC voltage and then to control the current value by means of a resistor or the like to light the LED lamp device.
The LED lamp device has increased its brightness and has secured a reliability, with the result that a demand for the LED lamp device has increased. However, in case the LED lamp device is connected to the commercial power source to light it up, there is the following disadvantage. Namely, as can be seen from the above-described construction, parts for lighting up such as a transformer, a resistor or the like become bigger in volume than the LED emitter. As a result, it is not possible any more to take advantage of the merit in that the LED emitter is small in size and, therefore, candescent lamps must be largely relied upon.
The present invention has been made in view of the above-described disadvantage and has an object of providing an LED lamp device that is small in size and can be used with the commercial power source or a DC power source of the voltage that corresponds to the voltage of the commercial power source.